This invention relates to a lens case for storing a pair of contact lenses, and more specifically, a case that can be used for storage as well as the disinfecting and/or sterilizing of said contact lenses.
The first contact lens developed were of the "hard" variety and disinfecting and/or sterilization of these was not a critical procedure, since this type of lens did not provide a suitable medium for bacteria growth. With the advent of newer "soft" contact lens certain problems have evolved, which were not heretofore encountered with respect to cleaning and sterilization procedure employed with hard lenses. Specifically, the soft contact lenses are generally manufactured from a hydrophilic plastic material, which is relatively porous such that it will absorb water, and become soft and pliable. The porous nature of this material provides a medium for bacteria growth, which can lead to eye infections, and thus necessitates relatively frequent, i.e. daily, disinfecting or sterilization, to prevent the accumulation of undesirable bacteria.
A number of sterilization methods have been developed for use with the soft contact lenses. A first one of these methods involves immersion of the lenses in a disinfecting solution, usually a saline solution, and heating of the solution to a temperature sufficient to destroy the bacteria that might be present. A second method that has been developed employs a chemical process to destroy bacteria and achieve sterilization. With regard to the heating method of sterilization this, in turn, may be accomplished by either a "wet heat" process or a more recently developed "dry heat" process. In the former process, the lenses are first placed in a case containing a saline solution and this case is then placed in a vessel of water which is brought to the boiling point, heat transfer to the sterilizing case and lenses in the solution therein being accomplished by the surrounding water. As can be appreciated, the water will be heated only to its boiling point, and as such the actual temperature advanced within the lens case will not exceed that of the water, and due to heat loss will be somewhat lower. In the second or "dry heat" method, the lenses are placed within a sealed or airtight case and the saline solution added, whereupon the case is positioned in direct contact with a dry heating element, such that there is direct application of heat to a surface of the case or container and hence to the sterilizing solution and lenses therein. With this method and the use of a sealed vessel, the solution can be superheated, that is heated to a level above the normal, atmospheric boiling point of the disinfecting solution.
The prior art includes a number of lens cases which were developed primarily for use in the "wet heat" process, for example as shown in U.S. Pat. Nos. 3,770,113; 3,977,517; 4,009,777. While these prior art cases work well in wet heat applications, and can be used in dry heat disinfecting process, they are possessed of certain shortcomings when used with the dry heat type of sterilization. In contrast, the lens cases of this invention, as will become apparent from the following description, are particularly well adapted for use in the dry heat sterilization process. Moreover, these lens cases include a number of advantageous features which render them useful for the storage of either hard or soft contact lenses, or for use in the wet heat type of sterilization process, as well.
More specifically, the lens cases of this invention are adapted to accommodate the lenses in a pair of similar pockets disposed in side-by-side relation in a relatively shallow flat casing structure. This casing structure, which includes a base member and a cover member, has at least one exterior flat surface area configured for broad surface-to-surface engagement with a heating element to facilitate and enhance heat transfer. A pair of similar pockets or compartments are defined by a partition in the base member of the case. This partition is provided with a suitable aperture or trough for assuring that a substantially equal amount of disinfecting solution will flow into the respective pockets, without regard for the point of introduction of the solution. The trough or aperture is sized, however, to preclude passage of a lens from one pocket to the other. Further, in a first embodiment the partition is of a height, such that when the cover is closed, its upper edge is closely spaced relative to the confronting inner surface of the cover member. As such should a lens inadvertently be interposed between the partition and inner cover surface, the lens will not be impinged upon or "pinched" to the extent that it will be damaged. However, this spacing is selected such that transmigration of a lens from one pocket to the other during rotation of the cover, is precluded. More specifically, the lenses are extremely pliable and in the wetted condition there is a possibility that they may adhere to the cover. In the event this occurs, rotation of the cover pursuant to opening may result in displacement of the lens from its assigned pocket, or the inadvertent depositing of a lens in the wrong pocket. With the first design, the partition effects a wiping action which will dislodge any lens adhered to the cover member. Moreover, the interior surfaces forming the pockets are generally curvilinear in cross section, substantially avoiding any recesses, sharp corners or the like where residue from the saline or other disinfecting solutions might otherwise accumulate. As will be more fully described hereinbelow, the interior surface of the cover member is provided with an irregular surface to prevent or discourage adherence of a lens thereto. In a second embodiment of the invention, a screen or apertured lid is pivotally connected to the base and overlies the partition and the pockets to maintain the lenses in proper location.
It will be appreciated that the foregoing structural considerations substantially prevent the respective lenses for the right eye and the left eye being confused or reversed, as the lenses will remain in the pockets in which they are initially placed. As a further matter in this regard, suitable indicia such as letters R and L are preferably included at suitable positions with respect to the two pockets, as a further indication of the lenses to be contained therein.